// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_TREES_CLIP_NODE_H_
#define CC_TREES_CLIP_NODE_H_

#include <memory>

#include "cc/base/cc_export.h"
#include "cc/trees/clip_expander.h"
#include "ui/gfx/geometry/rect_f.h"

namespace base {
namespace trace_event {
    class TracedValue;
} // namespace trace_event
} // namespace base

namespace cc {

struct CC_EXPORT ClipNode {
    ClipNode();
    ClipNode(const ClipNode& other);

    ClipNode& operator=(const ClipNode& other);

    ~ClipNode();

    // The node index of this node in the clip tree node vector.
    int id;
    // The node index of the parent node in the clip tree node vector.
    int parent_id;
    // The layer id of the layer that owns this node.
    int owning_layer_id;

    enum class ClipType {
        // The node doesn't contribute a new clip. It exists only for caching clips
        // or for resetting clipping state.
        NONE,

        // The node contributes a new clip (that is, |clip| needs to be applied).
        APPLIES_LOCAL_CLIP,

        // This node represents a space expansion. When computing visible rects,
        // the accumulated clip inherited by this node gets expanded. Similarly,
        // when mapping a rect in descendant space to the rect in ancestor space
        // that depends on the descendant rect's contents, this node expands the
        // descendant rect. This is used for effects like pixel-moving filters,
        // where clipped-out content can affect visible output.
        EXPANDS_CLIP
    };

    ClipType clip_type;

    // The clip rect that this node contributes, expressed in the space of its
    // transform node.
    gfx::RectF clip;

    // For nodes that expand, this represents the amount of expansion.
    std::unique_ptr<ClipExpander> clip_expander;

    // Clip nodes are used for two reasons. First, they are used for determining
    // which parts of each layer are visible. Second, they are used for
    // determining whether a clip needs to be applied when drawing a layer, and if
    // so, the rect that needs to be used. These can be different since not all
    // clips need to be applied directly to each layer. For example, a layer is
    // implicitly clipped by the bounds of its target render surface and by clips
    // applied to this surface. |combined_clip_in_target_space| is used for
    // computing visible rects, and |clip_in_target_space| is used for computing
    // clips applied at draw time. Both rects are expressed in the space of the
    // target transform node, and may include clips contributed by ancestors.
    gfx::RectF combined_clip_in_target_space;
    gfx::RectF clip_in_target_space;

    // The id of the transform node that defines the clip node's local space.
    int transform_id;

    // The id of the transform node that defines the clip node's target space.
    int target_transform_id;

    // The id of the effect node that defines the clip node's target space.
    // TODO(crbug.com/642581 crbug.com/642584): As we progress toward SPv2 and
    // layer list mode, there may be layers having the same clip but draw onto
    // different target. Target information shall be removed from here.
    int target_effect_id;

    // When true, |clip_in_target_space| does not include clips from ancestor
    // nodes.
    bool layer_clipping_uses_only_local_clip : 1;

    // True if layers with this clip tree node need to be drawn with a clip
    // applied.
    bool layers_are_clipped : 1;
    bool layers_are_clipped_when_surfaces_disabled : 1;

    // Nodes that correspond to unclipped surfaces disregard ancestor clips.
    bool resets_clip : 1;

    bool operator==(const ClipNode& other) const;

    void AsValueInto(base::trace_event::TracedValue* value) const;
};

} // namespace cc

#endif // CC_TREES_CLIP_NODE_H_
